Final answer:
The total resistance of a parallel circuit with a 15-ohm light bulb and a 20-ohm resistor is approximately 8.57 ohms.
Step-by-step explanation:
A parallel circuit contains resistors that are connected in parallel, meaning that the current splits and flows through each resistor individually. To find the total resistance of the circuit, you can use the formula:
1/RTotal = 1/R1 + 1/R2 + ...
In this case, the resistors have resistance values of 15 Ω and 20 Ω. Plugging these values into the formula, we get:
1/RTotal = 1/15 + 1/20
Simplifying this equation gives us:
1/RTotal = (4 + 3)/60
1/RTotal = 7/60
RTotal = 60/7 ≈ 8.57 Ω
Therefore, the total resistance of the circuit is approximately 8.57 Ω.